AWS introduced IPv6 only VPCs last year[1] and it made many AWS APIs endpoints unreachable from IPv6 instances as they are IPv4 only. So they are adding IPv6 support to them[2]. You can expect more of these type of blog posts this year.

[1] https://news.ycombinator.com/item?id=29327190

[2] https://news.ycombinator.com/item?id=29767004

Compliance with federal policies: https://aws.amazon.com/blogs/publicsector/aws-enables-us-fed...

Interesting trickle down effect from governments having a lot of purchasing power.

This is all about being able to invoke AWS Lambda from an IPv6-only network. Their copy states as much: "(...) removes the need for expensive networking equipment to handle address translation between IPv4 and IPv6."

Use cases will be IPv6-only networks with no NAT64 capabilities, either due to compliance reasons or because you're running, eg, IoT devices that need to call home over a provided 3G/4G connectivity and you were only able to get competitive prices if you stayed away from the cellular provider's IPv4 stack.

Increased margins for AWS as the shortage of public IPv4 makes the price per IP more and more expensive. You may also save a few $ per year.

I doubt it. They still default to giving an EC2 machine a public IPv4; if their primary motivation would be saving IP costs, they could easily go for the low-hanging fruit.

EC2 is not really low hanging fruit. Most expect to get a ipv4 when creating an instance and many relies on that. Cheaper instances with ipv6 only is probably coming

That's very likely. Hetzner already offers cheaper ipv6-only dedicated servers: https://news.ycombinator.com/item?id=29471986

EC2 is their oldest service; I bet it has oodles of legacy workflows both on Amazon's side and on customers' side. Lambda is likely a much lower hanging fruit in terms of the effort required to make changes to it.

To be pedantic, SNS is their oldest service, if I remember my AWS training correctly.

You are thinking of SQS, the preview version of which was the first to be introduced. S3 was the first non-preview service made generally available.

Correct - you know your AWS launch history!

The number of deployed lambdas likely exceeds the number of ec2 instances by many multiples (pure conjecture). It's a perfect use-case for v6 - dual stack in front and then v6 internally.